1. Field of Invention
The present invention relates to a lighting system including collimators aligned with light emitting segments.
2. Description of Related Art
Semiconductor light-emitting devices including light emitting diodes (LEDs), resonant cavity light emitting diodes (RCLEDs), vertical cavity laser diodes (VCSELs), and edge emitting lasers are among the most efficient light sources currently available. Materials systems currently of interest in the manufacture of high-brightness light emitting devices capable of operation across the visible spectrum include Group III-V semiconductors, particularly binary, ternary, and quaternary alloys of gallium, aluminum, indium, and nitrogen, also referred to as III-nitride materials. Typically, III-nitride light emitting devices are fabricated by epitaxially growing a stack of semiconductor layers of different compositions and dopant concentrations on a sapphire, silicon carbide, III-nitride, or other suitable substrate by metal-organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), or other epitaxial techniques. The stack often includes one or more n-type layers doped with, for example, Si, formed over the substrate, one or more light emitting layers in an active region formed over the n-type layer or layers, and one or more p-type layers doped with, for example, Mg, formed over the active region. Electrical contacts are formed on the n- and p-type regions.
An adaptive lighting system is a system where the beam pattern projected is selectively altered. For example, in an adaptive lighting system for an automotive headlight, the beam pattern projected anticipates the direction of the automobile and selectively alters the beam pattern to produce light in that direction.
US 2004/0263346, which is incorporated herein by reference, describes the solid state adaptive forward lighting system shown in FIG. 1. The system of FIG. 1 includes an array 42 of light emitting diodes (“LEDs”) 43. Each row of the array 42 is electrically connected to a horizontal LED driver 36, and each column of the array 42 is electrically connected to a vertical LED driver 34. The horizontal and vertical drivers 36 and 34 are attached to a central processing unit 28. A wheel angle sensor 20 and an incline sensor 24 are both attached to the central processing unit 28. A converging lens (not shown in FIG. 1) is positioned in front of the array 42. Upon receiving signals from the wheel angle sensor 20 and the incline sensor 24, the central processing unit 28 communicates with the horizontal and vertical LED drivers 36 and 34, to illuminate selected LEDs 43 in the array 42. Light rays from the LEDs 43 are angled by the lens, such that the selective illumination of one or more of the LEDs 43 in the array 42 allows the headlamp to project light in variable horizontal and vertical directions. Horizontal and vertical lines connected to each LED in the array terminate into a horizontal bus 38 and a vertical bus 40, respectively. The horizontal bus 38 is in electrical communication with the horizontal LED driver 36, and the vertical bus 40 is in electrical communication with the vertical LED driver 34. Each of the horizontal lines 60 and vertical lines 62 terminates in an associated switch, which is operable by the horizontal LED driver 36 and the vertical LED driver 34, respectively.